2 * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173
4 * Copyright (C)2003 USAGI/WIDE Project
6 * Author Mitsuru KANDA <mk@linux-ipv6.org>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
26 * The compression of IP datagram MUST be done before AH/ESP processing,
27 * fragmentation, and the addition of Hop-by-Hop/Routing header.
30 * The decompression of IP datagram MUST be done after the reassembly,
33 #include <linux/module.h>
36 #include <net/ipcomp.h>
37 #include <asm/semaphore.h>
38 #include <linux/crypto.h>
39 #include <linux/pfkeyv2.h>
40 #include <linux/random.h>
41 #include <linux/percpu.h>
42 #include <linux/smp.h>
43 #include <linux/list.h>
44 #include <linux/vmalloc.h>
45 #include <linux/rtnetlink.h>
48 #include <net/protocol.h>
49 #include <linux/ipv6.h>
50 #include <linux/icmpv6.h>
51 #include <linux/mutex.h>
54 struct list_head list
;
55 struct crypto_comp
**tfms
;
59 static DEFINE_MUTEX(ipcomp6_resource_mutex
);
60 static void **ipcomp6_scratches
;
61 static int ipcomp6_scratch_users
;
62 static LIST_HEAD(ipcomp6_tfms_list
);
64 static int ipcomp6_input(struct xfrm_state
*x
, struct sk_buff
*skb
)
67 struct ip_comp_hdr
*ipch
;
69 struct ipcomp_data
*ipcd
= x
->data
;
71 struct crypto_comp
*tfm
;
74 if (skb_linearize_cow(skb
))
77 skb
->ip_summed
= CHECKSUM_NONE
;
79 /* Remove ipcomp header and decompress original payload */
80 ipch
= (void *)skb
->data
;
81 skb
->transport_header
= skb
->network_header
+ sizeof(*ipch
);
82 __skb_pull(skb
, sizeof(*ipch
));
86 dlen
= IPCOMP_SCRATCH_SIZE
;
90 scratch
= *per_cpu_ptr(ipcomp6_scratches
, cpu
);
91 tfm
= *per_cpu_ptr(ipcd
->tfms
, cpu
);
93 err
= crypto_comp_decompress(tfm
, start
, plen
, scratch
, &dlen
);
97 if (dlen
< (plen
+ sizeof(*ipch
))) {
102 err
= pskb_expand_head(skb
, 0, dlen
- plen
, GFP_ATOMIC
);
107 skb
->truesize
+= dlen
- plen
;
108 __skb_put(skb
, dlen
- plen
);
109 skb_copy_to_linear_data(skb
, scratch
, dlen
);
118 static int ipcomp6_output(struct xfrm_state
*x
, struct sk_buff
*skb
)
121 struct ip_comp_hdr
*ipch
;
122 struct ipcomp_data
*ipcd
= x
->data
;
125 struct crypto_comp
*tfm
;
128 /* check whether datagram len is larger than threshold */
129 if (skb
->len
< ipcd
->threshold
) {
133 if (skb_linearize_cow(skb
))
138 dlen
= IPCOMP_SCRATCH_SIZE
;
142 scratch
= *per_cpu_ptr(ipcomp6_scratches
, cpu
);
143 tfm
= *per_cpu_ptr(ipcd
->tfms
, cpu
);
145 err
= crypto_comp_compress(tfm
, start
, plen
, scratch
, &dlen
);
146 if (err
|| (dlen
+ sizeof(*ipch
)) >= plen
) {
150 memcpy(start
+ sizeof(struct ip_comp_hdr
), scratch
, dlen
);
152 pskb_trim(skb
, dlen
+ sizeof(struct ip_comp_hdr
));
154 /* insert ipcomp header and replace datagram */
155 ipch
= ip_comp_hdr(skb
);
156 ipch
->nexthdr
= *skb_mac_header(skb
);
158 ipch
->cpi
= htons((u16
)ntohl(x
->id
.spi
));
159 *skb_mac_header(skb
) = IPPROTO_COMP
;
162 skb_push(skb
, -skb_network_offset(skb
));
167 static void ipcomp6_err(struct sk_buff
*skb
, struct inet6_skb_parm
*opt
,
168 int type
, int code
, int offset
, __be32 info
)
171 struct ipv6hdr
*iph
= (struct ipv6hdr
*)skb
->data
;
172 struct ip_comp_hdr
*ipcomph
=
173 (struct ip_comp_hdr
*)(skb
->data
+ offset
);
174 struct xfrm_state
*x
;
176 if (type
!= ICMPV6_DEST_UNREACH
&& type
!= ICMPV6_PKT_TOOBIG
)
179 spi
= htonl(ntohs(ipcomph
->cpi
));
180 x
= xfrm_state_lookup((xfrm_address_t
*)&iph
->daddr
, spi
, IPPROTO_COMP
, AF_INET6
);
184 printk(KERN_DEBUG
"pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT
"\n",
185 spi
, NIP6(iph
->daddr
));
189 static struct xfrm_state
*ipcomp6_tunnel_create(struct xfrm_state
*x
)
191 struct xfrm_state
*t
= NULL
;
192 u8 mode
= XFRM_MODE_TUNNEL
;
194 t
= xfrm_state_alloc();
198 t
->id
.proto
= IPPROTO_IPV6
;
199 t
->id
.spi
= xfrm6_tunnel_alloc_spi((xfrm_address_t
*)&x
->props
.saddr
);
203 memcpy(t
->id
.daddr
.a6
, x
->id
.daddr
.a6
, sizeof(struct in6_addr
));
204 memcpy(&t
->sel
, &x
->sel
, sizeof(t
->sel
));
205 t
->props
.family
= AF_INET6
;
206 if (x
->props
.mode
== XFRM_MODE_BEET
)
207 mode
= x
->props
.mode
;
208 t
->props
.mode
= mode
;
209 memcpy(t
->props
.saddr
.a6
, x
->props
.saddr
.a6
, sizeof(struct in6_addr
));
211 if (xfrm_init_state(t
))
214 atomic_set(&t
->tunnel_users
, 1);
220 t
->km
.state
= XFRM_STATE_DEAD
;
226 static int ipcomp6_tunnel_attach(struct xfrm_state
*x
)
229 struct xfrm_state
*t
= NULL
;
232 spi
= xfrm6_tunnel_spi_lookup((xfrm_address_t
*)&x
->props
.saddr
);
234 t
= xfrm_state_lookup((xfrm_address_t
*)&x
->id
.daddr
,
235 spi
, IPPROTO_IPV6
, AF_INET6
);
237 t
= ipcomp6_tunnel_create(x
);
242 xfrm_state_insert(t
);
246 atomic_inc(&t
->tunnel_users
);
252 static void ipcomp6_free_scratches(void)
257 if (--ipcomp6_scratch_users
)
260 scratches
= ipcomp6_scratches
;
264 for_each_possible_cpu(i
) {
265 void *scratch
= *per_cpu_ptr(scratches
, i
);
270 free_percpu(scratches
);
273 static void **ipcomp6_alloc_scratches(void)
278 if (ipcomp6_scratch_users
++)
279 return ipcomp6_scratches
;
281 scratches
= alloc_percpu(void *);
285 ipcomp6_scratches
= scratches
;
287 for_each_possible_cpu(i
) {
288 void *scratch
= vmalloc(IPCOMP_SCRATCH_SIZE
);
291 *per_cpu_ptr(scratches
, i
) = scratch
;
297 static void ipcomp6_free_tfms(struct crypto_comp
**tfms
)
299 struct ipcomp6_tfms
*pos
;
302 list_for_each_entry(pos
, &ipcomp6_tfms_list
, list
) {
303 if (pos
->tfms
== tfms
)
312 list_del(&pos
->list
);
318 for_each_possible_cpu(cpu
) {
319 struct crypto_comp
*tfm
= *per_cpu_ptr(tfms
, cpu
);
320 crypto_free_comp(tfm
);
325 static struct crypto_comp
**ipcomp6_alloc_tfms(const char *alg_name
)
327 struct ipcomp6_tfms
*pos
;
328 struct crypto_comp
**tfms
;
331 /* This can be any valid CPU ID so we don't need locking. */
332 cpu
= raw_smp_processor_id();
334 list_for_each_entry(pos
, &ipcomp6_tfms_list
, list
) {
335 struct crypto_comp
*tfm
;
338 tfm
= *per_cpu_ptr(tfms
, cpu
);
340 if (!strcmp(crypto_comp_name(tfm
), alg_name
)) {
346 pos
= kmalloc(sizeof(*pos
), GFP_KERNEL
);
351 INIT_LIST_HEAD(&pos
->list
);
352 list_add(&pos
->list
, &ipcomp6_tfms_list
);
354 pos
->tfms
= tfms
= alloc_percpu(struct crypto_comp
*);
358 for_each_possible_cpu(cpu
) {
359 struct crypto_comp
*tfm
= crypto_alloc_comp(alg_name
, 0,
363 *per_cpu_ptr(tfms
, cpu
) = tfm
;
369 ipcomp6_free_tfms(tfms
);
373 static void ipcomp6_free_data(struct ipcomp_data
*ipcd
)
376 ipcomp6_free_tfms(ipcd
->tfms
);
377 ipcomp6_free_scratches();
380 static void ipcomp6_destroy(struct xfrm_state
*x
)
382 struct ipcomp_data
*ipcd
= x
->data
;
385 xfrm_state_delete_tunnel(x
);
386 mutex_lock(&ipcomp6_resource_mutex
);
387 ipcomp6_free_data(ipcd
);
388 mutex_unlock(&ipcomp6_resource_mutex
);
391 xfrm6_tunnel_free_spi((xfrm_address_t
*)&x
->props
.saddr
);
394 static int ipcomp6_init_state(struct xfrm_state
*x
)
397 struct ipcomp_data
*ipcd
;
398 struct xfrm_algo_desc
*calg_desc
;
408 ipcd
= kzalloc(sizeof(*ipcd
), GFP_KERNEL
);
412 x
->props
.header_len
= 0;
413 switch (x
->props
.mode
) {
415 case XFRM_MODE_TRANSPORT
:
417 case XFRM_MODE_TUNNEL
:
418 x
->props
.header_len
+= sizeof(struct ipv6hdr
);
423 mutex_lock(&ipcomp6_resource_mutex
);
424 if (!ipcomp6_alloc_scratches())
427 ipcd
->tfms
= ipcomp6_alloc_tfms(x
->calg
->alg_name
);
430 mutex_unlock(&ipcomp6_resource_mutex
);
432 if (x
->props
.mode
== XFRM_MODE_TUNNEL
) {
433 err
= ipcomp6_tunnel_attach(x
);
438 calg_desc
= xfrm_calg_get_byname(x
->calg
->alg_name
, 0);
440 ipcd
->threshold
= calg_desc
->uinfo
.comp
.threshold
;
446 mutex_lock(&ipcomp6_resource_mutex
);
448 ipcomp6_free_data(ipcd
);
449 mutex_unlock(&ipcomp6_resource_mutex
);
455 static struct xfrm_type ipcomp6_type
=
457 .description
= "IPCOMP6",
458 .owner
= THIS_MODULE
,
459 .proto
= IPPROTO_COMP
,
460 .init_state
= ipcomp6_init_state
,
461 .destructor
= ipcomp6_destroy
,
462 .input
= ipcomp6_input
,
463 .output
= ipcomp6_output
,
464 .hdr_offset
= xfrm6_find_1stfragopt
,
467 static struct inet6_protocol ipcomp6_protocol
=
469 .handler
= xfrm6_rcv
,
470 .err_handler
= ipcomp6_err
,
471 .flags
= INET6_PROTO_NOPOLICY
,
474 static int __init
ipcomp6_init(void)
476 if (xfrm_register_type(&ipcomp6_type
, AF_INET6
) < 0) {
477 printk(KERN_INFO
"ipcomp6 init: can't add xfrm type\n");
480 if (inet6_add_protocol(&ipcomp6_protocol
, IPPROTO_COMP
) < 0) {
481 printk(KERN_INFO
"ipcomp6 init: can't add protocol\n");
482 xfrm_unregister_type(&ipcomp6_type
, AF_INET6
);
488 static void __exit
ipcomp6_fini(void)
490 if (inet6_del_protocol(&ipcomp6_protocol
, IPPROTO_COMP
) < 0)
491 printk(KERN_INFO
"ipv6 ipcomp close: can't remove protocol\n");
492 if (xfrm_unregister_type(&ipcomp6_type
, AF_INET6
) < 0)
493 printk(KERN_INFO
"ipv6 ipcomp close: can't remove xfrm type\n");
496 module_init(ipcomp6_init
);
497 module_exit(ipcomp6_fini
);
498 MODULE_LICENSE("GPL");
499 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
500 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
502 MODULE_ALIAS_XFRM_TYPE(AF_INET6
, XFRM_PROTO_COMP
);